1·Such disease has features of chanciness and suddenness, So long-term tracking and treatment is necessary to prevent cardiovascular.
这类病症具有偶然性和突发性的特点，要防治这类疾病就必须对患者进行长时间的跟踪治疗。
2·Most faults happening seems to be chanciness, in fact the hidden trouble range and its sequence can be found from catenary parameters before its operation.
目前大多数故障的发生看似具有一定的偶然性，其实从其运行前的参数就可以知道故障的隐患范围和可能发生的结果。